Cutting over iSCSI LUNs between filers

[mattmusgrove1]

I need to cutover from one FAS to another, a task I have accomplished many times before using SnapMirror to transfer the data.  Using OnTap 7.3.7

Previously I have only had to cutover CIFS and NFS, however on this occasion I also have two iSCSI LUNs.

How does the new FAS recognise the LUNs which were created on the original FAS? I assume I will also need to configure initiator groups.

I can't see any config files in my etc directory in the root volume which relate to iscsi.

Can someone advise on the right way to migrate iSCSI LUNs between filers?

[billshaffer]

I have done this before.  Snapmirror the data, and the new controller will see the luns with "lun show".  You're right, you'll need to configure the inititator groups, etc.

One caveat - luns have a serial number that I don't believe is copied with snapmirror.  Some applications (Exchange comes to mind) are picky about this serial number; they won't let you use data on a different lun serial, even though it's the same drive letter.  List the existing lun's serial with "lun serial <lun_path>", and set the new lun's serial with "lun serial <lun_path> <serial>".

Bill

[nitish · Accepted solution]

1. Unmount iSCSI LUNs on hosts
2. Shut down iSCSI on filer
   o iscsi stop;iscsi status
3. Perform snapmirror update
4. Perform snapmirror break
5. Make a copy of iscsi nodename from the orignal source filer
6. Modify nodename <dfiler> iscsi nodename
   o iscsi nodename [<new_nodename>]
   o iSCSI target nodename: iqn.1992-08.com.netapp:sn.118055087
7. Create igroups on filer and verify initiators are logged in
   o igroup create -i -t windows <igroup> <iqn>
8. igroup show –v
9. Note the orignal LUNs Serial number
10. Change LUNs to original serial number
    o priv set advanced;lun offline <LUN>
11. lun serial <LUN> Hnd5CZjW3OrO
12. lun online <LUN>
13. Map LUNs with iSCSI initiator groups and verify
    o lun map <LUN> <igroup> <LUN_id>
14. lun show -v <LUN>
15. Check to see if hosts can mount LUNs.  If not, reboot and re-verify
    o Restart iSCSI service on hosts if necessary
    o Remount iSCSI LUNs on hosts
    o iscsi session show (used to verify iSCSI session)

I found the above steps to be a cleaner way to migrate LUNs to new filer.

[aborzenkov]

Yes, you will need to manually create igroups and mapping on destination filer - they are not replicated. Also LUN serial numbers will change - this may be problem depending on host OS (e.g. VMware will not mount them by default).